JPH0438666Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a cutter for mowing weeds that grow naturally in gardens, mountains, fields, etc.

Conventional technology In general, a brush cutter is equipped with a small engine at the rear end of a long horizontal handle. Rotational power is guided from this engine to the tip of the handle by a transmission shaft running along the handle via a reduction gear and a friction clutch. Rotational power is transmitted to a vertical rotating shaft provided at the tip of the handle via a bevel gear.

To operate the above-mentioned brush cutter, the worker hangs the rear end of the handle on his shoulder via a hanging cord, supports the handle with one or both hands, and moves it forward while swinging it from side to side. Weeds are cut down using a cutter attached to the blade. A throttle lever for the engine is provided at the rear end of the handle, allowing for hand control of the engine speed.

As a conventional cutter for a brush cutter, as shown in FIG. 5, one in which a plurality of blade portions 1 are provided at equal positions on the outer circumference of a horizontal disk is known.

Problems to be Solved by the Invention In this type of brush cutter, the worker swings the handle from side to side centering on the waist, so the swinging trajectory of the tip of the handle is centered around the front of the worker. It swings left and right and up and down, and at both left and right ends, the rotation axis of the tip of the handle is not perpendicular to the ground but is tilted, which causes the tip of the cutter blade 1 to hit a stone, etc. on the ground and break off. There were other problems.

Further, in the brush cutter cutter a, the blade portion 1 has a substantially rectangular shape, and the blade edge surface 1a is aligned with the central axis O.
Since the blade edge side is a straight line that is slightly inclined backward in the direction of rotation with respect to the straight line N that passes through the There is a problem that they tend to escape to the outside, reducing mowing efficiency.

Particularly, since the wear of the blade portion 1 is more severe toward the cutting edge, the angle of inclination of the cutting edge surface 1a toward the rear in the rotational direction with respect to the straight line N gradually increases as the wear progresses, and the above-mentioned problem becomes even more pronounced.

In addition, since the blade part 1 of the brush cutter a has a substantially rectangular shape, stress concentration occurs in the base parts 1b, 1b of the blade part 1 due to the impact when cutting weeds, resulting in cracks. There is.

Means for Solving the Problems The present invention was proposed in view of the above-mentioned problems of conventional cutters for brush cutters. An annular flat part formed around the hole with a size corresponding to the boss part of the rotating shaft, and an upwardly curved annular flat part extending from the outer periphery of the annular flat part and curved toward the side corresponding to the boss part of the rotating shaft. A curved part and a curved part are formed at equal positions on the outer circumference of the upwardly curved part, the cutting edge surface is a straight line inclined forward in the rotational direction, the outer peripheral edge is a curved line that gradually becomes smaller in diameter backward in the rotational direction, and the trailing edge is the same as the cutting edge surface. It is equipped with a plurality of blade portions having substantially parallel curves, and a blade chamber formed by deeply recessing radially inward at the base between the blade portions and having an arcuate bottom portion.

Function The brush cutter of the present invention rotates at a position higher than the other parts of the blade, so even if the rotating shaft at the tip of the handle is tilted relative to the ground, it will not hit stones on the ground. There is no damage to the cutting edge, reducing damage to the cutting edge and allowing you to work with peace of mind.

Further, when cutting weeds, a component force is generated on the blade edge surface of each blade portion of the cutter for a brush cutter of the present invention in a direction that draws the weeds into the inside of the blade chamber. Since the blade chamber is formed deeply in the radial direction, there is little resistance when weeds are drawn into the blade chamber. Furthermore, since the width of each blade portion in the rotational direction is large, the strength in the rotational direction when cutting weeds is large, and it is possible to polish the blade many times. Furthermore, since the bottom of the blade chamber is formed in an arc shape, stress in the rotational direction when cutting weeds is not concentrated at the base of each blade, but is dispersed toward the annular flat part in the center. This prevents cracks from forming. In addition, each blade part is formed with an upwardly curved part on the outer periphery of the annular flat part, so even if a bending force is applied to any of the blade parts in the direction of the center of the cutter due to the impact during cutting, there will be no bending deformation. The starting point is not the base of each blade,
This is the boundary between the annular flat part and the upwardly curved part on the center side of the cutter.Since this boundary is annular, stress concentration does not occur, and the elastic restoring action is large, so the original shape is maintained. It has the effect of returning it to . Furthermore, since the cutting edge surface is a straight line, polishing is easy.

Embodiment FIG. 1 is a top view showing an embodiment of a cutter for a brush cutter according to the present invention, FIG. 2 is a bottom view, FIG. 3 is a side view, and FIG. 4 is a sectional view taken along the line - hand,
10 shows the cutter of the present invention.

The cutter 10 of the present invention has a plurality of blade parts 11 at equal positions on the outer circumference, a boss hole 12 in the center that is attached to the rotation shaft of the brush cutter, and a rotation shaft of the brush cutter around the boss hole 12. The size corresponds to the boss part of the shaft,
In addition, an annular flat portion 13 is formed that allows a fastener such as a nut to come into close contact with a flat surface when attached to the rotating shaft, and the outer peripheral portion of the annular flat portion 13 is curved toward the side corresponding to the boss portion of the rotating shaft. upward curved portion 14
is formed. The radius of curvature of this upwardly curved portion 14 is adapted to the ground height of the worker's waist when holding the rear end of the handle of the brush cutter and swinging it from side to side, and is, for example, an arcuate surface with a radius of 500 mm. .

The cutting edge surface 11a of each blade part 11 has the cutting edge 11a' side at a slight angle [for example, 10° to 15°, preferably about 13°] toward the front in the rotational direction [arrow S] with respect to the straight line N passing through the central axis O. It is a slanted straight line.

The blade chamber 15 formed between each blade part 11, 11 is
It is formed deeply in the radial direction.

In addition, the width of each blade portion 1 in the rotation direction is increased, and
It is formed substantially uniformly in the radial direction.

Furthermore, the bottom portion 15a of each blade chamber 15 is formed in an arc shape.

Further, each blade portion 11 is formed in an upwardly curved portion 14 on the outer peripheral side of the annular flat portion 13 .

The outer peripheral edge 11b of each blade part 11 is formed to have a diameter that gradually decreases toward the rear in the rotation direction, and the trailing edge 11c following this outer peripheral edge 11b is the same as the cutting edge surface 11a of the blade part 11. It is formed into a generally parallel gentle curve so as to be continuous with the blade chamber bottom portion 15a of the next blade portion 11.

The cutting edge surface 11a of each blade portion 11 is formed by grinding from the lower surface side, as shown in FIG.

The cutter 10 of the present invention uses a material plate suitable for cutlery such as carbon tool steel, is punched and formed using a press, and in the next step, the upwardly curved portion 14 is drawn, and the cutting edge surface 11a is ground and hardened. The thickness of the material plate is, for example, 1.4 mm.
The number of blade parts 11 is approximately 6 as shown in the drawing.
Not limited to sheets.

The cutter 10 having the above structure is mounted with the boss hole 12 on the rotating shaft at the tip of the handle of a brush cutter with the surface in FIG. 1 facing upward. In this case, the area around the boss hole 12 is
Since the annular flat part 13 is formed, the annular flat part 13 can be accurately attached to a brush cutter made by any manufacturer, with the annular flat part 13 orthogonal to the rotating shaft at the tip of the handle.

To cut weeds, start the engine of the brush cutter, hold the rear end of the handle, and swing the tip of the handle horizontally from side to side. In this case, cutter 10
Since the outer peripheral portion is curved upward, the blade portion 11 is less likely to collide with the ground, and mowing work can be performed safely. Since the blade edge surface 11a is inclined forward in the direction of rotation, when cutting weeds, a force that pulls the weeds into the blade chamber 15 acts, and the weeds captured by the blade part 11 are removed from the outside. It can be cut reliably without letting the material escape. Furthermore, since each blade chamber 15 is formed deeply in the radial direction, there is little resistance to weeds that are drawn into the blade chamber 15 by the blade edge surface 11a. Furthermore, by curving the outer periphery of the cutter 10,
During rotation, buoyancy is generated, making the swinging operation of the handle easy. Furthermore, by increasing the width of each blade portion 11 in the rotational direction and forming the blade chamber bottom 15a in an arc shape, the strength in the rotational direction is increased.
No stress concentration or cracks occur at the base of each blade part 11,
The stress is gently dispersed toward the annular flat portion 13 side. Furthermore, since each blade portion 11 is formed in an upwardly curved portion 14 on the outer peripheral side of the annular flat portion 13, an elastic restoring action can be obtained against the bending action of the blade portion 11 toward the center of the cutter 10. It will be done. moreover,
The cutting edge surface 11a is inclined forward in the direction of rotation,
In addition, by increasing the width of each blade portion 11 in the rotation direction, polishing can be repeated many times depending on the wear of the blade edge surface 11a, and in this case, the inclination of the blade edge surface 11a in the rotation direction can be reduced. Although the angle gradually moves backward, it maintains good sharpness for a long period of time. Further, since the cutting edge surface 11a is linear, even an amateur can easily polish it.

Effects of the invention According to the invention, it is possible to cut weeds while pulling them into the blade chamber, and furthermore, it is possible to smoothly pull weeds into the blade chamber, and the shape of the blade part is geometric. Since the shape is scientifically buoyant, it is possible to reduce the operating effort of the brush cutter by generating buoyancy during rotation, and it also disperses the stress caused by the impact during cutting without difficulty, and is also good for bending action. It can exert a strong elastic restoring effect, preventing cracks at the base of the blade and breakage of the cutting edge, allowing safe work.Also, the upward curved part allows you to fly cut weeds far away. It is possible to obtain effects such as:

[Brief explanation of the drawing]

Fig. 1 is a top view showing an embodiment of a cutter for a brush cutter according to the present invention, Fig. 2 is a bottom view, Fig. 3 is a side view, Fig. 4 is a sectional view taken along the line - - of Fig. 1, and Fig. 5 FIG. 1 is a top view showing an example of a conventional cutter for a brush cutter. 10... cutter, 11... blade part, 11a...
Blade edge surface, 12...boss hole, 13...annular flat part,
14...Upward curved part, 15...Blade chamber.

Claims (1)

[Scope of Claim for Utility Model Registration] Having a boss hole in the center that is attached to the rotating shaft of the brush cutter, and an annular flat part formed around the boss hole with a size corresponding to the boss part of the rotating shaft. , an upwardly curved part extending on the outer periphery of the annular flat part and curved toward the side corresponding to the boss part of the rotating shaft, and an upwardly curved part formed at equidistant positions on the outer periphery of the upwardly curved part to move the cutting edge surface forward in the direction of rotation. A plurality of blade parts each having an inclined straight line, an outer peripheral edge having a curve that gradually becomes smaller in diameter toward the rear in the rotational direction, and a trailing edge having a curve approximately parallel to the cutting edge surface, and a base between each blade part that extends radially inward. A cutter for a brush cutter characterized by having a blade chamber that is deeply recessed and has an arcuate bottom.